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Re-flashing basics

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We don't have a course addressing this, though I did see one webinar where to touched on the subject.

As such, I know it will be difficult to explain here but can you give me the basics on how you go about approaching a tuning strategy for a re-flash?

I saw the webinar where you did it on an 86 I believe and you only addressed the WOT area of the map. I could see why, because as you explained each change you make needs to be flashed back to the stock ecu and this can take a while.

Obviously with this constraint it would not be practical to re tune the part throttle areas of the map in steady state because I assume this would take forever quite literally.

What then is you tuning approach when dealing with re flashing? Do you only touch up the WOT area?

A little more insight into to topic would be appreciated.

Thanks a lot,


I'd also like to know a little about this as I'm just about to start bit of flashing but the chosen car can't be don't by obd so I do it off eeprom and in winols to edit.

When working with OEM ECUs some software's will allow live tuning, this is only if you are lucky. If your not then it will be a case of a lot of data collection and adjustments.

I watched a stream recently of a tuner dealing with one of the new Ford F150 lightning's with their ecoboost engines and they said it would take them 3 weeks to develop a comprehensive tune for this vehicle if they were lucky. The engine was modified by full race so had larger Turbos etc.

If the engine isn't too modified from stock them it'll only be the WOT areas that will change out with areas that trims can't take care of, if you have dramatically changed the VE of the engine then you'll need to set aside a lot of time.


Do you have specific experience reflashing the evo x? If not is there anyone on here that you know that does?


I can't say I do, my previous employ was a Subaru specialist and I deal in mostly Nissan and Toyota's now with the odd Subaru.


I want to find out if ecuscan has the definition file for a 2009 JDM GSR evo X.

Also, from your experience.....can you do open loop boost control using a factory car with the OEM ecu? I've seen Andre doing it in the boost control course using a stand alone but can this be done on a standard car using reflash?


It's impossible for me to do justice to a complete description on reflashing here but I'll give you some basic direction.

The approach will vary a little depending on what exactly you've done to the engine or how modified it is. For example on a stock or lightly modified engine you can all but ignore the idle, cold start and cruise areas of the mapping (basically any time the engine is operating in closed loop) and focus solely on the WOT open loop area. This is a huge time saver compared to tuning a standalone ECU.

The process is to make a ramp run on the dyno, log the ECU (particularly you want to log parameters associated with knock feedback, load point and rpm which will depend on the particular ECU). You can then make changes to the map, flash the new map into the ECU and test the effect of those changes.

My process is much the same as with a standalone ECU in that I like to get the fuel dialed in first followed by the ignition timing. If you have a variable cam control engine like the EVO X then this adds another element in that you can adjust the cam timing too. Another advantage with reflashing an OE ECU is that the base cam timing maps are already going to normally be pretty close in my experience. This again speeds up the process because you don't need to start from blank maps and it's sufficient usually to try adding/subtracting 5 degrees from the cam map and testing to see what the result was.

This is very generic and basic but hopefully it's been of some use. The EVO X is probably one of the most conservative factory tunes I've seen in a stock car and there are significant areas for improvement. On my old Dynapack dyno a stock JDM EVO X made less power than a stock JDM EVO 9 (about 180 kW atw vs about 190) but from memory with no hardware changes this can be improved to about 220-230 kW atw. Some basic bolt ons such as exhaust, intake and intercooler hard pipes nets around 250 ish so the scope for improvement.

NOTE: It's been a number of years since we did this development work on the EVO X so the numbers I quoted above might not be 100% accurate.

Thank for the response Andre.

I believe there is a patch available now on ecuscan to do live tuning of the fuel, ignition and mivec maps. I am going to look into this since it will make things much easier.

Here's one other thing I'd like you to touch on. From my reading I see mitsubishi uses a parameter defined as "load" for their maps but it is not a MAP signal. From what I've read its a combination of the MAP and MAF readings. When tuning boost control this can become tricky tuning the map using this parameter and then relating it back to a boost pressure of MAP reading. How would you deal with this?

Also I have another question for you. I've noticed on the stock evo x the boost pressure goes to a maximum then tapers off as the rpm increases. If the car has a factory installed boost control strategy, why does this happen? Shouldn't it be tuned from the factory to hold relatively steady boost?

This leads me to my next question. Seeing that reflash software does not have a live cursor to show you where in the maps you are accessing in real time, would it be beneficial to re-tune the factory boost control strategy to target more steady boost levels before attempting to tune the timing and fuel maps? If you dont do this then it may be a bit challenging to know where to adjust in the map?

Typically the load value should end up 'close' to manifold pressure in kPa absolute - ie 250% load would equate to about 22 psi. This isn't always 100% reliable though so the best advice I can give you is to log the load and compare that to the actual boost pressure. When you're raising the boost in particular this logging can help you derive what your new boost targets need to be in order to achieve your desired boost levels while achieving stable closed loop feedback.

The stock boost curve is quite typical for a factory turbo car and it's like that for two reasons. First the high boost at low rpm provides a lot of low down torque which makes the engine feel fast and responsive. Secondly the turbo becomes restrictive at high rpm and this limits the boost you can produce. On a stock EVO X you won't be able to maintain a 100% flat boost curve, however if you fit a larger turbo this may be possible.


Can you give some general guide lines on selecting a boost target curve? I saw in all the webinars and in the boost control course you targeted a flat curve throughout the WOT area. The car I am going to tune is fitted with a bigger turbo so as you say it may be possible to target a flatter curve although I am not sure of the response I will get because the car is still on a standard 2 port boost solenoid. I am guessing fuel type might have a factor in this in order to keep the engine safe ? I am tuning on relatively low octane 95RON fuel so maybe I might be safer tapering the boost off as I approach red line?

Really it's up to you and the size of the turbo fitted, although yes, a 3 port solenoid is going to give superior control.

With a small/medium size turbo it's not uncommon for the turbine inlet pressure to rise to the point where the wastegate is forced open at high rpm and consequently the boost will drop off. If you have a reasonable size turbo then there's no reason why you can't keep the boost flat provided the engine is physically strong enough. On 95 you're likely to be knock limited anyway so this will ultimately limit the amount of boost you can run.

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